The invention relates generally to dual-medium articles, which advantageously combine two mediums such as metal and a paper-based sheet material.
One embodiment of the invention more particularly relates to polygonal dual-medium articles, such as collectible trading cards (e.g. baseball trading cards), bookmarks, and similar articles, of various sizes and shapes.
Traditionally, collectible trading cards have been made of thin cardboard, with a photograph on one side, and information printed on the other side.
Recently, for permanency and enhancement of appearance, it has been proposed to make such cards of lithographed sheet metal, for example as is disclosed in Miller U.S. Pat. No. 5,215,792. However, one disadvantage of such metal trading cards is that it is difficult, if not impossible, to achieve on sheet metal the quality of printing which can be achieved on other sheet materials, particularly paper-based sheet materials.
Another disadvantage, recognized in the above-referenced Miller patent, is that a raw piece of sheet metal contains sharp edges and corners which would make such a piece unsafe for use as a trading card. In view of this, Miller proposes a construction wherein the edges are folded to form flat hems presenting radiused surfaces at least on the outer edges of the card, leaving unfolded edges only at the corners, which unfolded edges are short in length.